Tape for driving pulleys



A. K. LANDAU TAPE FOR DRIVING FULLEYS Jan. 1, 1952 Filed Sept. '15, 1949 2 SHEETS-SHEET l Jan. 1, 1952 A. K. LANDAU TAPE FOR DRIVING PULLEYS 2 SHEETSSHEET 2 Filed Sept. 15, 1949 'ZWVGWZQ? I w KW M,M,2Kmv

Patented Jan. 1, 1952' TAPE FORDRIVINGRULLEYS Alfred K; Landau, Newtonville, 'Mass., assignor to Lambeth Rope Corporation, New

Bedford;

Mass. a corporation of Massachusetts Application. September-15, 194,9, SerialNo. 115,809.

6, Claims:

This invention relates to endless tapes or bands foruse .in drivingcrowned pulleys andmoreparticularly to tapes employed to drive. crowned whorl type spindles in the spinning and twisting; of textile strands. In one aspect, this invention consists in a tapehaving. a loosely woven mid.- portion whereby flexibility of the tape is improved, substantial power is saved, and a more even distributionof contact on the whorl iseffected. In another aspect this, invention consists in a tape having increased porosity in its mid-portion. whereby. the air. normally entering between the tape and the whorl passes through the tape Without causing any substantial disconformity in the tape. Still another aspect of my invention, consists in a tape having a midportion which is thinner and in which the longitudinal strength members have been reduced or omitted whereby the main driving force of the tape will be applied more at the margins of the tape where it will engage the whorl or pulley in the area of reduced radius of the whorl or pulley above and below the crest of the, crown.

I have found that, in usein driving crowned pulleys such as thewhorls of a. spinning frame or twister, the following points should be kept firmly in mind: First the friction of bending a tape increases as the. cube of the tapes thickness, therefore the tape should be kept as thin as possible. Second, the tape should he, kept thin, for another reason. is a function of the speed radius of the whorl plus one, half of the thickness of the tape. Thus the. the-whorl spin. under identical conditions of power consumption, or to put it more aptly, the thinner tape. the whorl at the.

thinner the tap the faster will can travel slower, but yet drive correct speed. Third, in a vertical, crowned whorl it is desirable whorl, in order to obtain the benefit of the reduced radius of the whorl off the-crest of the crown. Fourth, the strength of the tape is important and cannot be sacrificed beyond a certain minimum, however, failure of tapes generally occurs at the point of connection between the ends of the tapes and not by virtue of strength failure. Therefor high strength is not a prerequisite. A fifth consideration relates to what is known as scuffing. When a. tape drives firmly against the crest of the crown, the margins of. the tape also come into. contact with the whorl above and below the crest. Since the radius of the whorl is less in the area above and below the crest of the crown, and the tape is travelling at a. greater speed than that part. of the whorl, the tape marconstructing tapes forv to have the tape .drivenear.-

gins constantly rub against. the whorl. Such. microscopic but assumes.

rubbing. is of course substantial proportions over extended operations.

Sixthli, it should'be bornein mind thatithe tape attempts to drag air in between itself and the whorl. This results in the tape, ballooning or puckering out in the middle after extended. use

and eventually hastensfailure through uneven and the. skin friction between the tape and thesurrounding air. This latter consideration as. sumes substantial proportions in aspinning mill having, for instance, 50,000 spindles. During the operations of suchv a mill, therewill of 25 miles of tape, all travelling at about .20 milesper hour. The skinfriction to the surrounding air issubstantial, and since the said friction. increases as the. tapes velocity, it will be seen that the slower the tape travels, the better, other things being equal.

Tapes have been constructed in the past without any special recognition for these factors. They range in thickness from. .035 to .077", have a weight equivalent of 25 to yards per pound, and a breaking strength between .200 lbs. and 2.80 lbs. Y tight basket or herringbone weave generally wide and when on. the whorl they drive. directly on the crest of the crown .thereof. Some thought has. been given to reinforcing the center of the tape in order to reduce the tendency of the tape.

of the. optimum efliciency that I. have found. to.

be obtainable.

Among the objects of my invention is the provision of a tape which will be comparable; to conventional tapes in other ways, but which will present less. friction to bending in conformance with the crown of the whorl. Another object-of my invention is to provide. a drive primarly at its margins, crest of the. crownpf the whorl. jectof my invention is to provide a tape. whichwill not pucker after extended use. and which will present a substantially uniform. surface contact against theobject of my invention is the provision of: a tapewhich willbe, able to travel. slower thanxconventional tapes thereby reducing windageloss, but at. the same. time. drive the spindle at the same speed, as the conventionaltape. I

In the'accomplishment of these; objects, inapreferredembodiment, I weavethe tape in the .A further. ob-

be. a totalof r the tape cube of the They are generally woven in a crown of the. whorl. Another 2,581,261 f ,F'l

conventional manner, but instead of employing a full warp, I leave out one or more of the central warp strands or ends. It is a feature of my invention that the tape thus produced has a partial gap down its center line. It is thinner in its mid-portion than conventional tapes and thereby presents less friction to transverse bending. Also longitudinal bending is slightly improved. Furthermore, the reduced thickness centrally figures in increasing whorl R. P. M. By omitting a plurality of the central warp strands, the tape load at the crest of the crown is distributed on less warp strands than conven tionally and consequently they stretch more than the marginal strands. This tends to shift the load out towards the margins of the tape, off the crest of the crown, and in the area of reduced radius. The increased porosity of the tape caused by the omission of the warp strands likewise serves to vent the air trapped between the whorl and tape, thereby reducing puckering and promoting even wearing conditions. Furthermore, the reduced bulk of the tape centrally also reduces the inertia in that area and in turn reduces the tendency to pucker."

In one embodiment of the novel tape of my invention, I employ filling strands of reduced size either as a feature alone or in conjunction with I other features of my invention mentioned above. In this way I am able to reduce the average thickness of the tape without impairing its longitudinal strength. In general, it is an accepted principle in textile manufacture that the best results are obtained when the warp and filling are the same size. However, I have discovered that this principle does not apply to the special case of tapes, and that an improved construction is obtained by making the tape in direct contravention to the said principle.

In another embodiment of my invention, I employ center warp strands of reduced weight, thereby improving the bending qualities of the tape, promoting marginal drive, reducing scuffing and puokering.

Further objects and features of my invention will bestbe understood and appreciated from a detailed description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawings, in which:

Fig. l is a fragmentary, greatly magnified, diagrammatic plan view of the mid-portion of the tape of my invention, showing four warp strands omitted,

Fig. 2 is a view in side elevation showing the ends of the tape sewn together as for forming an endless drive tape,

Fig. 3 is a plan view of the arrangement shown in Fig. 2,

Fig. 4 is a fragmentary view in cross section of the mid-portion of the tape of my invention showing four warp strands omitted,

Fig. 5 is a view in side elevation of the spindle with the tape, partially in section, on the whorl,

Fig. 6 is a cross sectional view of the tape of my invention employing reduced size central warp strands, and

Fig. '7 is a cross sectional view illustrating the tape of my invention employing a reduced size filling strand.

In the preferred embodiment herein shown in Fig. 1 the tape is illustrated as a herringbone weave, with four of its central warp strands omitted as indicated at I2. It is wide, is .035" thick at its margins, and has 4| warp strands or ends [4. The warp strands or ends are staple cotton having a weight equiv"- alent of 16/3 and are set up as for 45 ends with spaces where the central four would otherwise be. For filling Hi, the tape is provided with 30 strands or picks per inch, likewise having a weight equivalent of 16/3. This tape has a breaking strength of 172.4 lbs. which is slightly lower than conventional tape but which I have found to be satisfactory in operation.

In its application to a spinning frame, a length of the tape is out ofi and both ends thereof are sewn together to form an endless tape, as shown in Figs. 2 and 3. Thereupon the tape is placed on the whorls in the conventional manner with the tape seating midway on the crown III as shown in Fig. 5.

In Fig. 4, it will be seen that the area in the center of the tape indicated at I2 is substantially thinner than towards the margins of the tape. Thus, crown of the whorl, the area of the tape where the principal bending friction takes place, the center, will present substantially less resistance to bending than conventional tapes. Furthermore, due to the absence of warp strands centrally, the air impelled between the whorl and tape will vent through the tape rather than causing any disconformity or puckering. The absence of center warp strands also tends to shift the load off the crest of the crown to the tape margins and the area of smaller radius on the whorl.

In addition to this it will be noted that inasmuch as the tape is thinner centrally where it bears upon the crest of the crown and thicker towards its edges, there will be less scuffin action due to conformance to the crown of the whorl than in conventional tapes.

During actual operations, the warp strands will tend to shift partly towards the center and tend to equalize the gap made by the omission of the central warp strands. However, due to the fact that the crown will bear also in this area, there is a counter tendency for the warp strands to separate and remain in compression against the marginal warp strands. Therefore the center remains substantially porous and thinner, and the warp strands never actually equalize the spacing between them.

Tests have demonstrated that with a pulley of diameter to drive the tape turning at 2820' R. P. M., and with a whorl diameter of 1 6", the spindle speed developed by the tape herein described as a preferred embodiment will be 10,500 R. P. M., and that the power consumption will be on the order of 169 spindles per horsepower.

Conventional tapes on the whole achieve results vastly inferior to this, generally developing in the neighborhood of only 10,200 revolutions on the spindle to 2820 revolutions on the driving pulley and have horsepower equivalents of between 67 i and 122 spindles per horsepower. If the conventional tape is brought down to a thickness of around .035, it will develop only about 10,350 revolutions for a driving pulley speed of 2820 and its horsepower equivalent will be in the neighborhorsepower. This horsepower equivalent seems to measure favorably with my tape, but it must be borne in mind that with my tape it will be possible to reduce the R. P. M. of the driving motor by over 2%, and thereby effect a power saving through reduced windage and friction loss of upwards of 4% Another embodiment of the tape of my invention is shown in part sectionally in Fig.

when the tape bends to conform to the' 6 and inch of the remainder of the tape.

areas thereof, the said warp comprises 46 warp strands or ends having weights and being arranged as follows: 15 ends at 16/3 as indicated by reference numeral I4, 15 ends at .20/2 as indicated by reference numeral 20 and 16 ends at 16/3; and 30 picks per inch at 16/3 as indicated by reference numeral 16. Tape so constructed has most of the same desirable characteristics as the tape described in the preferred embodiment above. However, it will be noted that the venting action of the preferred embodiment will be greater than in the embodiment now being described. Tests have shown that the tape constructed in this manner will only develop 10,350 R. P. M. on the spindle for a driving pulley speed of 2820 R. P, M. However the horsepower equivalent for this embodiment of my tape is considerably higher, being 190 spindles per horsepower. This likewise represents an efliciency saving of upwards of of the entire power consumption of the spindle tape drive.

In Fig. 7 the tape is shown as having a reduced size filling or pick 18. This may be employed in either the embodiment wherein ends are omitted or in the embodiment wherein the ends are of reduced size. The reduction of the pick size has some eifect in reducing the strength of the tape but it is to be noted that such reduction is not critical, and is more than oifset by the efiiciency saving attained by the reduction in thickness of the tape.

As for the type of weave of the tape, herringbone or other twill weave fabric is preferred but it is to be understood that basket or other types of weaves are permissible. The invention herein described is not intended to be limited to the type of weave. However, it is significant to note that herringbone weave seems to present less skin friction to the air and therefore is preferable for spindles.

Numerous variations of the embodiments herein shown are possible without departing from the spirit of the invention. For instance the central ends may be of reduced size and also some of them may be omitted. The important factor in this connection being that the central one third of the cross section of the tape is going to weigh substantially less per inch as a total mass than one half the combined weight per In the preferred embodiment outlined above I calculate this central one third to be about 20% lighter, whereas the embodiment having reduced size center warp strands, the center warp strands weigh as much as 40% less, taken as a mass.

Since further variations will now be apparent to those skilled in the art, it is not intended to confine the invention to the precise limits of the embodiments herein described but rather to limit it in terms of the appended claims.

Having thus described an illustrative embodiment of the process of my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An endless driving tape for a crowned pulley comprising warp strands spaced to form a tight weave transversely of the tape in the marginal strands spaced apart in the central area of the tape to form a loose weave along the said central area thereof, and filling strands spaced evenly along the entire length of the said tape, whereby the tape will have increased porosity and flexibility in the said central area, will be thinner in the said central area so that the central area will are over the central portion thereof, and will bear on the pulley in the marginal areas of the tape to each side of the crown of the said pulley to effect the main driving force between the tape and the pulley.

2. An endless driving tape for a crowned pulley comprising warp strands extending longitudinally of the tape, and filling strands extending transversely of the tape, the said warp strands being spaced in the marginal two thirds of the tape at the rate of strands to the total width of the tape, and at a similar rate in the central one third thereof with a plurality of warp strands omitted, so that the central one third of the tape is more flexible than the outer thirds to are over the crowned portions of a pulley and wherein the outer thirds effect the main driving force.

3. A drive tape for a crowned pulley comprising a twill weave fabric having warp strands extending longitudinally of the tape, filling strands of a substantially lighter weight than the said warp strands interwoven therewith, the said warp strands being spaced further apart in the mid area than at the margins thereof as by omitting a central warp strand in the weaving of the tape, so that the central one third of the tape is more flexible than the outer thirds to are over the crowned portions of a pulley and wherein the outer thirds effect the main driving force.

4. A drive tape for a crowned pulley comprising a twill weave fabric having warp strands extending longitudinally of the tape, filling strands interwoven therewith, and the total weight per inch of the center one third of the tape being substantially less than onehalf the total weight per inch of the tape in the remaining two thirds of the tape, so that the central one third of the tape is more flexible than the outer thirds to are over the crowned portions of a pulley and wherein the outer thirds effect the main driving force.

5. A drive tape as described in claim 4 further characterized by the total weight per inch of the center one third of the tape being at least 20% less than one half of the total weight per inch of the tape in the remaining two thirds of the tape.

6. An endless driving tape for a crowned pulley comprising warp strands extending longitudinally of the tape, filling strands interwoven therewith, and the total weight per inch of the center one third of the tape being substantially less than one half of the total weight per inch of the tape in the remaining two thirds of the tape, so that the central one third of the tape is more flexible than the outer thirds to are over the crowned portions of a pulley and wherein the outer thirds effect the main driving force.

ALFRED K. LANDAU.-

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

